Gearless hydro-mechanical transmission

Abstract

A hydro-mechanical transmission 10 having fluid motor 48 that is entirely rotatable to eliminate the need for separate gearing is disclosed. The gearless hydro-mechanical transmission 10 provides a variable speed and torque output from an external mechanical power source 14 and an external hydraulic power source 20. The hydro-mechanical transmission 10 comprises a stationary case 42, an output shaft 44 mounted within the case for rotation about a central axis 52, a mechanical input 46 mounted in coaxial alignment with the output shaft 44 for rotation about the central axis 52 with the input 46 being connected to and rotatable driven by the mechanical power source 14, a rotatable hydraulic motor 48 having a drive unit 60 for rotatably driving a driven unit 62 with the driven unit 62 being coupled to drive the output shaft 44, and means 100 for conducting pressurized hydraulic fluid from the hydraulic power source 20 to the hydraulic motor 48 for driving the driven unit 62 of the hydraulic motor 48 by the drive unit 60.

I claim: 
     
       1. A gearless hydro-mechanical transmission for providing a variable speed and torque output from an external mechanical power source and an external hydraulic power source, comprising: a stationary case having a first inlet/outlet port and a second inlet/outlet port;   an output shaft mounted within said case for rotation about a central axis;   a mechanical input mounted in coaxial alignment with said output shaft for rotation about said central axis, said input being connected to and rotatable driven by said mechanical power source;   a rotatable hydraulic motor having first and second fluid chambers, and a drive unit for rotatably driving a driven unit, said driven unit being coupled to drive said output shaft; and   means for conducting pressurized hydraulic fluid from said hydraulic power source to said hydraulic motor for driving said driven unit of said hydraulic motor by said drive unit, said means including a pressure manifold, an annular port plate, an annular pressure force manifold, a distributor valve, and first and second passage means, said pressure manifold being carried by said case, said port plate being carried by said pressure manifold, said distributor valve being carried by and rotatable with said drive unit of said hydraulic motor, said pressure force manifold being carried within said valve, and said first and second passage means each being separately disposed through said case, pressure manifold, port plate, pressure force manifold and distributor valve to separately conduct fluid from said first and second inlet/outlet ports, respectively, to said first and second chambers of said hydraulic motor.   
     
     
       2. The transmission of claim 1 wherein said port plate has a radially disposed sealing face thereon and said pressure force manifold has a mating radially disposed sealing face thereon disposed in face sealing rotatable contact with said sealing face of said port plate. 
     
     
       3. The transmission of claim 2 wherein said distributor valve has a double stepped annular opening therethrough and said pressure force manifold has a mating double stepped outer periphery that is slidable received within said stepped opening of said valve and provides a pair of pressure chambers therebetween, each chamber being in communication with a respective one of said first and second passage means to create an axial force for urging said sealing face of said pressure force manifold into sealing contact with said face of said port plate. 
     
     
       4. The transmission of claim 3 wherein driven unit has a central opening therethrough, said opening having an internal spline engaged with a mating external spline on said output shaft. 
     
     
       5. The transmission of claim 4 wherein said hydraulic motor is a low speed, high torque type motor. 
     
     
       6. The transmission of claim 5 wherein said hydraulic motor is a radial piston motor and said drive unit is a cam unit and said driven unit is a piston unit. 
     
     
       7. The transmission of claim 4 wherein said hydraulic motor is an axial piston motor and said drive unit is a swash plate unit and said driven unit is a piston unit. 
     
     
       8. The transmission of claim 4 including means for rotatably supporting said hydraulic motor to permit the rotation of said motor relative to said stationary case about said central axis.